Annealing furnace



Feb. 17, 1948. L.. E. SMITH 2,435,024

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ANNEALING runnen 6 Sheets-Sheet 6 Filed Jan. 20, 1942 mama ret. 11. 194s2,436,024 y UNITED srA'ras PATENT ortica ANNEALING FURNACE LeanderEugene Smith, Kokomo, Ind., assigner to Continental Steel Corporation,Kokomo, Ind., a corporation of Indiana Application January 20, 1942,Serial No. 427,505

s claims. (ci. zes-4s) This invention relates to annealing furnaces,

particularly for annealing sheets, although capable of use for annealingother material, for example, wire, and hence not so limited. Theinvention more especially pertains to that type of annealing furnacewherein after the sheets or charge of other materials arey piled on thehearth, an inner cover formed of good heat conducting metal is placedover the sheets to enclose same, vfollowing which the outer cover, orthe furnace proper is placed over the inner cover, with both coverssupported on the base or bottom of the furnace. and sealed from theingress or infiltration of air bysand, oil, or equivalent, the coversbeing spaced to provide `a heat. ing and combustion chamber in suchspace.

Following the application of heat, for'sufllcient a period of time toanneal the charge, the outer cover is removed and replaced with relationto another inner cover which latter encloses a second charge piled on asecond base, after which the heat is similarly applied to the innerlcover of the second charge, while the first charge, from Vincreases therapidity of heating of the inner cover, and which also applies the heatin a uniform manner so as to effect uniform heating of the batch orcharge of material.

A further object of the invention is to provide means for applying heatto the inner cover by maintaining a zone of ring with the nameenveloping and literally hugging the inside wall of the outer cover.

Still further the invention aims to provide heating means for the innercover which intercepts the flame and thereby not only directs or deectssame so as to -cause the flame to follow a acts to -direct or'deflectand spread the flame against the inside wall of the outer cover, andalso provides an increase of heat by radiation.

The invention further resides in means for holding the corrugated baieplate or tile in position and to provide means on the inside wall of theouter cover, which cooperates with the baille plate or tileto form aheat passage that deilects the heat so as to cause the flame to alwaysmaintain a position close to the inside wall of the cover.

The invention still further aims to control the heat supplied to theinner cove'r by providing a damper mechanism which is responsive. to thegas supply.

The invention has still other and further objectives which will be laterset forth and of themselves manifested in the course of the followingdescription.

In the drawings:

Fig. 1 is a vertical sectional view taken transversely through thecentral portion of a furnace constructed in accordance with the presentinvention;

path close to the inside wall of the outer imping- Fig. 5 is anelevation partly broken away, and

partly in section, of one of the bolts or fasteners employed to securethe refractory tile in position; Fig. 6 is a top plan view of thecorrugated or undulating refractory baille plates, showing the t mode ofconnecting the sections;

Fig. 7 is a front elevation of Fig. 6, partly broken away, of one of thebaille sections;

Fig. 8 is a fragmentary perspective view of the inner face of the sidewall of the outer cover;

Fig. 9 is a view similar to Fig. 5 of a modified form of bolt orfastener;

Fig. 10 is a fragmentary view of the top of the outer cover; and v Fig.11 is a fragmentary perspective view of the damper control.

In proceeding in accordance with the present invention and referringmore particularly to Fig.

1, l designates the hearth of the furnace which is formed of refractorymaterial and is provided with a trough 2, which surrounds and receivesas indicated at 3.

4other forms.

Therefore dependent upon the 'shape of the inner cover I, the trough 2is shaped to corre-V spond thereto so as to receive the entire bot tomportion of the inner cover and thereby seal same against the ingress orinfiltration of air.

The batch or stack of sheets or other chargeof material is initiallyplaced upon the sand filled portion B of the hearth, following which theinner cover 4 is applied in the position shown in Fig. 1.

The superstructure of the furnace, which will be referred to as thefurnace proper, is removable from the base structure, which latterincludes the hearth, and has a supplemental trough 6 provided below, andin surrounding relation to the trough 2. to likewise receive a sealingmaterial. The furnace proper has an arched top 8, ends 9' and sides 9formed of tile or refractory material, and held in place by a suitablemetal casing indicated generally at I0. The bottom of the casing has adepending web II secured thereto, which is received within the trough 6so as to form an air seal, as in the instance of the seal of the trough2.

Any suitable crane or grapple engaging member I2, is connected to thetop of the furnace proper, which constitutes the outer cover, so thatthe latter may be removed and replaced upon a second base correspondingin structure to that just described. to heat a second batch or charge ofmaterial while the rst batch or charge of material is cooling with theinner cover enveloping same to thereby prevent the ingress of air to thebatch, as shown in Fig. 1.

passages or chambers. and are corrugated or of undulating formation, soas to provide an increased heat radiating area which confronts the innercover l.

For the purpose of securing the baifiles in position, bolts havingrectangular heads 28, as

` shown in Fig. are employed, the latter being In the instance of afurnace of rectangular form such as herein illustrated the two oppositesides only are equipped with burners or heat generators which extendsubstantially throughout the length thereof. I'he sides 9 have theirinner walls formador faced with either refractory and/or refractoryinsulation material in brick or tile monolithic construction, andsimilar lower tiles Il, which coniointly form the inner faces of theside walls of the outer cover.

The tiles I4 are formed with substantially vertical lower faces I5;'outwardly curved or bulged intermediate portions I6, which merge at IIinto outwardly bulged upper portions I8, so that the heat from theburners will be directed inwardly of the tiles by the bulged portions I6and I8.

Vertically disposed spaced pilasters I4' are formed on the sides 9, andhave beveled sides which deflect and spread the heat and increaseradiation. The pilasters are located on opposite sides of the burners,and serve to provide a series of vertical alleys for the heat, and toalso support or reinforce the walls.

The bottoms of the walls of the furnace proper are chambered asindicated at I9, to receive insulation 20, upon which latter slabs 2land 23 formed of insulating material, are disposed, the

'latter forming the bottom or floor of the heat 'l walls of the heatsupplying passages, or chambers 2l, while' vertically disposed baiilesor plates 2B, are provided to form the innerwalls of such composed ofinner sections 21, and outer sections 28, the sections being preferablywelded in end to end relation as indicated at 29. Since the sections 2lare disposed in a zone subjected loy and has a rectangular head 2B'similar to ghe lsxead 26 of the form of the bolt depicted in 1g.

In Figs. 3 and 4, a modified form of side walls is disclosed, andwherein the bulge of the portions I6' is more pronounced and extendoutwardly from the vertical faces I6' to a greater degree, than in Fig.l. Further there are straight portions Il' which extend upwardly fromthe portions I6' and which terminate in straight inclined upper portionsI0', which deflect the heat inwardly. that depicted in Fig. 1.

The burners, generally Vindicated at 3l, are of any suitable type andare disposed within housings 32 formed of refractory material. Aiighting hole 33 for the burners is provided, as depicted in' Figs. 3and 8. A Aseries of lower abutments or projections lb, are formed on thetiles I4, and also upper abutments or projections I6b, to Vengage theupper and lower sides respectively of the bullies. the abutments Ib andI6b, forming seats against which the outer faces of the bailles engage,and are held seated by the heads of the bolts 26 or 26 which extendthrough the tiles Il, and securely engage the inner faces of thebailles, upon tightening of the nuts 30 of the bolts.

-'1'he top 8, of theouter cover and the top of the metal casing. is, asshown in Figs. l and l0. formed with a series of ilues 3l, which arecontrolled by dampers 35 that are connected to chains 36. The chains aresuspended from arms 31 that are rigidly connected to a shaft'38,suitably journaled on the top of the metal casing I0.

An arm 39 is rigidly connected centrally of its ends to an end of theshaft 38, and has a series of perforations for selective connection tothe upper end of a rod 4I, which latter is actuated by an automaticcontrol valve mechanism, not shown. This mechanism is responsive to theamount of gas supplied to the burners. Thus, if the gas supply is high,the dampers are fully opened, and if the supply is low the dampers arepartially closed, Consequently the opening and closing of the dampers isproportional to the amount of gas supplied to the burners.

The disclosure of the invention is that preferred. but it is to beexpressly understood that the same is susceptible to all changes,modifications and the 'like as fall within its scope and spirit,announced by the following claims.

Otherwise the structure is similar to What is claimed is:

1. In an annealing furnace of the type having a charge-receiving hearth,a removable inner cover for the charge, and a removable outer coverspaced from the inner cover to form a heating and combustion chambertherewith; a series of burners carried by theouter cover, and extendingat right anglesk to the side-wallj'f the latter, a lining for the outercover formi'/g one Wall of a heat conducting passage for the gases andhaving a substantially straight portion disposed above the burners andfurther having an inwardly bulged portion and an upper portion extendingvertically upward from said inwardly bulged portion, a bottom for thepassage located beneath the burners, and a vertically disposedcorrugated baille forming the other wall of the passage disposed betweenthe burners and the inner cover and spaced from each thereof, and havingits upper end spaced below the upper inclined portion of the rst-namedwall of the passage.

2. In an annealing furnace, a series of burners, a body having meansforming one wall of a heat supplying passage and having a substantiallystraight portion disposed above the burners and further having aninwardly bulged portion and an upper portioninclined inwardly andupwardly from the bulged portion, a, bottom for the passage locatedbeneath the burners, and a vertically disposed corrugated baille formingthe other wall of the passage and having its upper end spaced below theupperinclined portion of the rst named Wall of the passage.

3. In an annealing furnace, a base for supp0rt v ing a charge to be heattreated, a cover having an open bottom mounted on said base and havingside and end walls and a top provided with an outlet, the side walls ofthe cover having a plural' ity of spaced inwardly facing recessestherein adjacent the lower edges thereof, a baiiie carried by the coverin 'spaced relation to the rear walls defining said recesses and havingits upper edge terminating spaced from the upper walls dening saidrecesses so as to provide a heat conducting passage therebetween, and aplurality of spaced burners, one each in each of said recesses,projecting through the side walls of the cover adjacent the lower end ofthe baille and at right angles to the latter for directing a flamethereagainst, whereby heat from the burners will ow upwardly through theheat conducting passage between the upper edge of the baffle and theupper wall of the recess and then upwardly along the face of the sidewall of the cover-above the recesses and toward and through the outletin the top of the cover.

4. In an annealing furnace, a base for supporting a charge to be heattreated, a cover having a. top-wall. side walls, end walls and an openbottom mounted on said base, said top wall having a damper controlledoutlet therethrough, the side` walls of the cover each having aninwardly facing recess formed therein adjacent its lower edge, a burnerin each of said recesses, and a vertically extending baille disposed ineach of said recessesv in spaced relation to the wall dening the back ofthe recess and having 'its upper edge terminating spaced from the walldeilning the top of the recess so as to provide a heat conductingpassage therebetween, said baiiies each having their outer side faces invertical alinement with the inner side face of the side wall above theadjacent recess, whereby the heat from said burners is directed againstthe inner faces of the baies and then upwardly through the heatconducting passage between the upper edge of the baiile and the top wallof the recess along the face of the side wall of the cover above therecesses and toward and through said outlet.

5. In an annealing furnace, a base for supporting a charge to be heattreated, a cover mounted on said base having a top wall, side walls, endwalls, and an open bottom, said top wall having a damper controlledoutlet therethrough, said cover having at least one of its side wallsprovidedl with aninwardly facing recess adjacent itsy lower edge, abaffle carried by. the side wall in spaced relation to the Wall definingthe back of the recess and having its upper edge terminating spaced fromthe wall defining the upper end of the recess -so as to provide a.passage for the flow of hot gases therebetween, said baille having itsinner side face alined with the inner side face of the side wall of thecover above the recess, and a burner in said recess for directing hotgases against the outer side face of the bafile so as to be deflectedupwardly thereby and through the passage defined between the upper edgeof the baille and the upper end of the recess and then upwardly alongthe inner side face of the side wall of the cover toward and through thedamper controlled outlet in said top wall.

LEANDER EUGENE SMITH.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date' Re. 15,000 Stafford Dec. 7, 19201,247,015 Roth Nov. 20, 1917 1,599,165 Clark Sept. 7, 1926 1,734,871Morse -..c Nov. 5, 1929 2,024,024 Carpenter Dec. 10, 1935. 2,089,843Wilson Aug. l0, 1937 2,194,977 Hoak' Mar. 26, 1940 2,217,363 l Hoak Oct.29, 1940 2,276,971 Hoak Mar. 17, 1942 i FOREIGN PATENTS Number CountryDate 468,653 Germany Nov. 16, 1928

